Shower receptor installation method

ABSTRACT

A method of installing a shower receptor with improved control of moisture and trapped water with one or more of the following improvements: the flange is significantly higher above the threshold than prior art receptors so a membrane can overlap the flange without reaching the ledge; the ledge area has multiple steps adapted to meet the subwall and finish wall materials and position the subwall higher than the finish wall; caulk is strategically applied.

This application is a continuation of Ser. No. 10/910,733 filed Aug. 3,2004.

BACKGROUND OF THE INVENTION

This invention relates to a shower receptor or shower pan. Thisinvention also relates to a shower stall using the shower receptor. Thisinvention also relates to a bathtub.

One piece molded shower receptors are known in the art. U.S. Pat. No.2,757,385 to W. W. Whittick and U.S. Pat. No. 3,800,335 to AnthonyBuonaura disclose examples of conventional shower receptors. Theseshower receptors were designed to replace tile and mortar bed showerfloors which were prone to leaking. They were designed to mate withvarious conventional wall construction materials. Shower subwalls areconventionally constructed of cement mortar, gypsum board, cementitiousbacker, coated glass mat backer board, or cementitious coated foambacker board and the like. Shower wall surfaces are conventionallyfinished ceramic or porcelain tile, stone, marble or prefabricated sheetmaterials, which are attached with thin set mortar or adhesive.

Even though the conventional shower receptors may solve the problem ofwater leakage that is associated with tile shower floor construction,there are still water leakage problems associated with stone-, marble-or tile-covered interior shower walls. All tile and stone walls withgrout lines leak and pass water. Grout lines are not waterproof and theyare generally not maintained in a way that will prevent this occurrence.With age and use, cracks and/or holes may develop in the tile wall,allowing increasing amounts of water to seep into the wall. The waterwill travel horizontally and vertically behind the tile. When it reachesthe bottom of the wall, it generally cannot flow into the showerreceptor because the joint where the tile wall and the shower receptormeet is generally sealed with silicone or other caulk. The watertherefore travels horizontally until it finally escapes the showerenclosure, either soaking into adjacent walls or leaking onto floorsoutside the shower stall. Alternately, the trapped water may wick upwardinto the drywall, plaster or other subwall material of the shower walls.Either way, the water seepage behind the tile wall can cause significantdamage in shower stalls using conventional shower receptors.

When a bathtub is installed in a combination bathtub-showerinstallation, the bathtub functions in the same way as the showerreceptors described above. When tile, stone, or marble walls are used insuch installations, the same water seepage problems occur as in theshower stalls described above.

What is needed is a shower receptor for a shower stall or bathtubinstallation having a flange that is significantly higher than thethreshold and the ledge area. What is needed is a shower receptor havinga ledge area that is lower in elevation than the threshold. What isfurther needed is a shower receptor having weep valleys in all cornersof the ledge area. What is further needed is a shower receptor having aledge area with more than one step adapted for mating with varioussubwall materials. The inventive shower receptor meets these needs.

BRIEF SUMMARY OF THE INVENTION

The invention is directed to a shower receptor wherein the ledge areathat is adapted to support the subwall and finish wall materials isdisposed lower in elevation than the threshold. The invention is alsodirected to a shower receptor wherein the ledge area comprises multiplesteps, the outer steps being higher than the inner steps, all stepssloping inward and adapted to support or mate with shower wallmaterials. The invention is also directed to a shower receptor whereinthe ledge area has weep valleys located in each corner and slopingtoward the base and adapted for directing water toward the base. Theinvention is also directed toward a shower receptor having a verticalflange extending upward from the ledge area at least about three inchesabove the ledge. The invention is also directed toward a shower receptorhaving a raised curb formed on the outer edge of the threshold.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a prior art shower receptor.

FIG. 2 is a perspective view of a second prior art shower receptor.

FIG. 3 is a perspective view of one embodiment of the invention.

FIG. 4 is a perspective view of a second embodiment of the invention.

FIG. 5 is a side elevation sectional view of a third embodiment of theinvention.

FIG. 6 is a perspective view of a fourth embodiment of the invention.

FIG. 6A is a side elevation sectional view along line A-A of theembodiment of FIG. 6.

FIG. 6B is a fragmentary sectional view along line B-B of the embodimentof FIG. 6.

FIG. 7 is a cross section of an embodiment of the invention.

FIG. 8 is a cross section of an embodiment of the invention.

FIG. 9 is a cross section of an embodiment of the invention.

FIG. 10 is a perspective view of another embodiment of the invention.

FIG. 10A is a fragmentary sectional view along line A-A of theembodiment of FIG. 10.

FIG. 10B is a fragmentary sectional view along line B-B of theembodiment of FIG. 10.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 and 2 show prior art shower receptors. They have a base 1 slopedtoward a central drain hole 9. Sidewalls 2 extend upward from the edgesof the base 1 forming a pan. Ledge 3 extends horizontally, laterally,outward from the top edge of the sidewalls 2 on three sides. Ahorizontal threshold 5 extends horizontally from the top edge of thesidewall on the fourth side. Flange 4 extends upward from the outer edgeof the ledge. The height H of the flange above the ledge is typically upto about one inch in prior art shower receptors.

Referring to the prior art shower receptor of FIG. 1, the threshold andledge are disposed at the same height relative to the base. Weep valley7 may be present at the intersection of the ledge 3 and the threshold 5,but not in the other corners of the ledge 3.

Referring to the prior art shower receptor of FIG. 2, curb 6 extendsupward from the outer edge of the threshold 5. Threshold 5 and ledge 3are the same height relative to the base. Curb 6 and flange 4 are thesame height H above the threshold 5 and ledge 3, respectively. Theheight H is generally about one inch.

FIGS. 3 through 6 and 10 show several embodiments of the inventiveshower receptor. The one-piece, molded shower receptor of the inventionmay be formed from any suitable thermoset or thermoplastic moldingmaterial according to conventional molding techniques. For example,sheet molding compound (SMC) may be placed in a two piece mold andformed and cured under pressure and heat. SMC may comprise any of theknown suitable resins, fiber or particle fillers and reinforcements,pigments, curatives. Alternatively, a lamination process of more thanone suitable material may be used. For example, the receptor maycomprise a gel coat or a vacuum-formed acrylic sheet over layers ofchopped-glass reinforced resin and/or various reinforcing materials orstructures applied in an open mold. These construction details areoffered by way of example, not meant to limit the scope of theinvention.

The shower receptors of FIGS. 3 through 6 have a square footprint andare designed for use in shower stalls having square footprints with athreshold on one side and shower walls on the other three sides. As willbecome apparent from the following descriptions, the invention isadaptable for use in shower stalls having a rectangular or curvilinearor any other footprint. The invention is also adaptable for use incorner shower stalls having shower walls on two sides and a threshold onat least two sides. The invention is also adaptable for use incombination bathtub and shower installations as illustrated by thebathtub embodiment shown in FIG. 10.

Referring to FIG. 3, the square shower receptor of one embodiment of thepresent invention is shown having a base 1 sloped toward a drain hole 9which may be located anywhere in the base as long as it is at the lowestpoint. At its periphery, the base 1 curves upward forming vertical sidewalls 2 on all sides. In other words, sidewalls 2 extend upward from theedges of the base 1. Ledge 3 extends horizontally, laterally, outwardfrom the top edge of the sidewalls 2 on three sides. A horizontalthreshold 5 extends horizontally from the top edge of the sidewall onthe fourth side. Flange 14 extends upward from the outer edge of theledge 3. In an embodiment of the invention, the height HI of flange 14above ledge 3 and threshold 5 is at least about three inches, which issignificantly higher than conventional shower receptors. It has beenfound that increased flange height leads to improved water tightness ofthe shower stall for reasons that should become clear when installationof the shower receptor is discussed below.

Curb 16 extends upward from the outer edge of the horizontal surface ofthreshold 5. Curb 16 is adapted to prevent water egress over thethreshold. Typically a shower door is supported by a metal track whichis mounted on the threshold. The curb height above the threshold shouldbe at most about the height of the metal track so as not to interferewith the opening of the door. Thus the curb height is much less thanheight H1. Water typically leaks past the shower door and collects onthe threshold. In one embodiment of the invention the curb prevents thewater from leaving the shower receptor, instead directing the water backtoward the base. Conventional shower receptors have a flat thresholdsurface, possibly with some inward slope. Water that gets past theshower door is most likely to run out of a conventional shower receptorhaving a conventional threshold. The curb feature of this inventionsolves this problem.

In the embodiment of the invention shown in FIG. 3, weep valleys 17 aredisposed where ledge 3 intersects threshold 5 and are disposed parallelto the threshold. In addition, weep valleys 18 are disposed in eachcorner of the ledge 3 extending diagonally across the ledge from thecorner of the flange to the corner of the sidewall. Weep valleys 17 and18 slope toward the base, being adapted to collect water sitting on theledge and direct it toward the base. Prior art shower receptors haveonly had weep valleys 17 at the intersection of the threshold and theledge. Adding the additional weep valleys 18 to the other corners of theledge has been found to dramatically improve the drainage of trappedwater from behind tiled shower walls back into the base. The slope ofthe weep valleys toward the base is not particularly limited, but may beabout six degrees.

Referring to FIG. 4, a second embodiment of the invention is shownhaving similar base 1, sidewalls 2, and flange 14 at height H3 abovethreshold 15. Ledge 13 again extends laterally from the top of sidewall2 on three sides of the base. In this embodiment of the invention,however, the ledge 13 is disposed lower in elevation with respect to thebase than threshold 15. The difference in height H2 between ledge 13 andthreshold 15 may be up to about 6 inches. In one embodiment, H2 is inthe range from about 2 inches to about 5 inches. By disposing the ledgelower than the threshold, or in other words the threshold higher thanthe ledge, water trapped behind the tile wall of the shower is preventedfrom escaping the shower receptor when flowing horizontally along theledge. In cooperation with the improved water-trapping ability of thehigher threshold and lower ledge, weep valleys 17 and 18 provide greatlyimproved means of directing trapped water back into the base of theshower receptor. In an embodiment of the invention, height H3 of flange14 above threshold 15 is at least about one inch, and height H2 ofthreshold 15 above ledge 13 is about 2.5 inches. Thus, height H2+H3 offlange 14 above ledge 13 is at least about 3.5 inches.

Referring to FIG. 5, a cross section of a third embodiment is shownhaving similar base 1, sidewalls 2, and flange 14 at height H3 abovethreshold 15. Again, curb 16 is shown extending upward from the outeredge of threshold 15. In this embodiment of the invention, a morecomplex ledge area 23 extends laterally from the top of sidewall 2 onthree sides of the base. Ledge area 23 comprises two steps 21 and 22.First step 21 is disposed lower in elevation with respect to the basethan second step 22. First step 21 is also closer to the base thansecond step 22. Both steps may be sloped toward the base to facilitatedrainage of water toward the base. The amount of slope is notparticularly limited but may be up to about six degrees or more. In thisembodiment of the invention, ledge area 23 is disposed lower inelevation with respect to the base than threshold 15. The difference inheight H2 between ledge 23 and threshold 15 may be up to about 6 inches.In an embodiment of the invention, height H3 of flange 14 abovethreshold 15 is at least about one inch, and height H2 of threshold 15above ledge 23 is at least about 2.5 inches. Thus, height H2+H3 offlange 14 above ledge 23 is at least about 3.5 inches.

In cooperation with the improved water-trapping ability of the higherthreshold and lower ledge, weep valleys 27 and 28 provide greatlyimproved means of directing trapped water back into the base of theshower receptor. Weep valleys 27 and 28 are shown as having uniformdownward slope, extending from the bottom of the flange 14 to the top ofthe side wall 2. Thus, the depth of the valleys varies as it crosses theledge area because of the two steps which define one side of valleys 27and both sides of valleys 28. Alternatively, the weep valleys could bemade of uniform depth, thus having two steps.

Second step 22 is adapted in horizontal width to accommodate thethickness of the subwall materials used to construct the shower walls.For backer board subwalls, the width of second step 22 may be aroundhalf an inch. For plaster or scratch coat and mortar subwalls, the widthof second step 22 may be around one and a quarter inches. The first step21 is adapted in horizontal width to accommodate the thickness of theceramic tile, stone, or marble used to finish the shower walls,typically about one quarter to one half inch. Alternately, the firststep 21 may be adapted in horizontal width to accommodate the thicknessof prefabricated sheet material such as fiberglass wall panel, culturedmarble or the like. The lower and upper ledges differ in elevation by aheight adapted to prevent water trapped behind the tile from wickinginto the rough wall material. This height may be at least about ¼ inchaccording to Tile Council of America standards, but is not limited toany particular distance. The dual-step ledge feature of the presentinvention provides definite guidance during installation for location ofthe backer board, mortar bed or other subwall material. The dual ledgeassures that the base of the subwall will be higher than the lower edgeof the tile and the silicone bead. Thus trapped water will be preventedfrom wicking up the materials. Some conventional shower receptors haveno ledges at all to guide the installers, or to prevent the rough wallmaterials from contacting the shower pan and wicking up any water thatis available. Other conventional shower receptors have a ledge and atrough in close proximity so that water trapped in the trough canimmediately be wicked up into the rough wall material. Otherconventional shower receptors do not allow the subwall materials tooverlap the flange at all.

Referring to FIG. 6, a perspective view of a fourth embodiment is shownhaving similar base 1, sidewalls 2, and flange 14 at height H3 abovethreshold 15. Again, curb 16 is shown extending upward from the outeredge of threshold 15. In this embodiment of the invention, a morecomplex ledge area 34 extends laterally from the top of sidewall 2 onthree sides of the base. FIGS. 6A and 6B show that ledge area 34comprises three steps 31, 32 and 33. First step 31 is disposed lower inelevation with respect to the base than second step 32, which is lowerin elevation than third step 33. First step 31 is also closer to thebase than steps 32 and 33. All steps may be sloped toward the base tofacilitate drainage of water toward the base. The amount of slope is notparticularly limited. In this embodiment of the invention, ledge area 34is disposed lower in elevation with respect to the base than threshold15. The difference in height H2 (shown in FIG. 6) between ledge area 34and threshold 15 may be up to about 6 inches. In an embodiment of theinvention, height H3 (as shown in FIGS. 6 and 6A) of flange 14 abovethreshold 15 is at least about one inch, and height H2 (as shown in FIG.6A) of threshold 15 above ledge 33 is at least about 2.5 inches. Thus,height H2+H3 of flange 14 above ledge 33 is at least about 3.5 inches.

The steps 31-33 are adapted in horizontal width to accommodate thethickness of various subwall materials used to construct the showerwalls. For backer board subwalls, the width of third step 33 may bearound half an inch, thus providing a guide for installation ofhalf-inch thick subwalls. For plaster or scratch coat and mortarsubwalls, the width of second step 32 and third step 33 combined may bearound one and a quarter inches, thus providing a guide for installationof mortar subwalls. The first step 31 and second step 32 are adapted inhorizontal width to accommodate the thickness of the ceramic tile,stone, or marble used to finish the shower walls, typically about onehalf inch per step. Thus, the second step would be the guide for finishwall materials when half-inch backer board subwalls are used, but thefirst step would be the guide for finish wall materials when thickermortar subwalls are used. The three steps differ in elevation by aheight adapted to prevent water trapped behind the tile from wickinginto the rough wall material. This height difference may be at leastabout ¼ inch for each step according to Tile Council of Americastandards, but is not limited to any particular distance. The tri-stepledge feature of the present invention provides definite guidance duringinstallation for location of the backer board, mortar bed or othersubwall material. The tri-step ledge assures that the base of thesubwall will be higher than the lower edge of the tile and the siliconebead. Thus trapped water will be prevented from wicking up into thesubwall materials.

FIGS. 7-9 illustrate shower stalls constructed with the inventive showerreceptor and various shower wall materials. Referring to FIG. 7, anembodiment of the shower receptor is shown with a ledge area havingthree steps 31, 32, and 33. Furring strips 51 are mounted on stud 50 inorder to compensate for the thickness of flange 14. Water resistantbacker board 53 is mounted to studs, overlapping flange 14, and leavingabout a ½-inch gap GI between the bottom edge of the board and thirdstep 33. Mildew-resistant silicone sealant or equivalent caulk 61 isapplied to the gap G1. Tile 56 is attached to backer board 53 usingadhesive or bond coat 55, and caulk 62 is applied to the joint betweentile and second step 32.

Referring to FIG. 8, a shower installation comprising lath and plasteris shown for illustrative purposes. Membrane 52 is attached to stud 50,overlapping flange 14 at least one inch, but leaving gap G3 of at leastabout one inch between membrane 52 and third step 33. Subwall 54comprises scratch coat and mortar bed on lath. Gap G2 of about ¼ inchbetween bottom edge of subwall 54 and second step 32 is filled withcaulk 63. Tile 56 is attached to subwall 54 using adhesive or bond coat55, and caulk 64 is applied to the joint between tile and first step 31.A time- and cost-saving feature of this invention is that furring stripsto compensate for the thickness of the flange 14 and prevent movement ofthe membrane are not necessary, but are optional.

Referring to FIG. 9, a shower installation comprising prefabricatedsheet material 57 such as fiberglass wall panel, cultured marble or thelike is shown. Again, furring strips 51 are mounted to framing studs 50to provide a flat surface for mounting water resistant backer board 53.Gap G1 of about ¼ inch between bottom edge of backer board 53 and thirdstep 33 is filled with caulk 61. Sheet material 57 is applied to backerboard with suitable adhesive.

Referring to FIG. 10, a bathtub according to the present invention isshown. As in the other shower receptors, the bathtub has a base 71sloping toward the drain hole and surrounded by sidewall 72. The primarydifference between the bathtub and the shower receptors discussed aboveis that the bathtub has much taller sidewalls adapted for holding bathwater. The bathtub has on one side a horizontal threshold 75 extendingoutward from the top edge of the side wall 72. According to theembodiment shown, the outer edge of the threshold has a raised curb 76which prevents water from running off of the threshold onto the floor.On the other three sides, there is a horizontal ledge area 73 extendinglaterally from the top edge of the sidewall 72 and disposed lower inelevation than the threshold by a vertical distance H2 of about two toabout six inches. There is a vertical flange 74 extending upward fromthe outer edge of the ledge area 73. The flange 74 extends a distance H3of at least one inch above the threshold. The flange 74 also extends adistance H2+H3 of at least about three inches above the ledge area 73.The ledge area 73 may comprise one horizontal surface or a series ofmore than one step. For the embodiment shown in FIG. 10, ledge area 73comprises three steps 81-83. The purpose and dimensions of the secondand third steps 82 and 83 are the same as for shower receptors discussedabove. The first step 81 is typically wider in bathtubs than inshower-only receptors, providing a ledge for placing objects andcontainers used in bathtubs and for leverage for the user to get in andout of the tub. The four corners of the bathtub have weep valleys 77 and78. FIG. 10A is a magnified partial section near a rear corner weepvalley 78. FIG. 10B is a magnified partial section near a front cornerweep valley 77.

Other known features of shower receptors may be incorporated into thepresent invention without detracting from its usefulness. The horizontalthreshold surface 5 or 15 and horizontal ledge surfaces 3 or 13 or 23may be sloped toward the base to facilitate draining of water into thereceptor 1. The amount of slope is not particularly limited. The basemay be embossed with various surface patterns for esthetic purposes orto prevent slipping during use. The under side of the base may besupported or reinforced by various molded in web or rib features.Likewise the threshold, side walls, ledge or flange may have variousexternal support structures. The drain hole may be adapted for varioustypes of drain fixtures. The flange and side walls may be drafted orslightly sloped outward from the base to facilitate demolding and/ornested stacking of shower receptors for storage or shipping. Showerreceptors adapted for use as bathtubs may have one or more holes in thebase and/or sidewall for drain hardware, jets, and the like. The tilingflange may be extended in front of the threshold as illustrated in FIG.10. Other optional features will be apparent to one skilled in the art.

Conventional methods of installation of a shower receptor include thesteps of fitting the receptor into a framed alcove so that it sitslevel; fastening (for example with nails or screws) the flange to thestuds; applying backer board, scratch coat and mortar bed, or othersubwall material to the studs so that the subwall abuts the top edge ofthe flange, or preferably overlaps the flange and stops just short ofthe horizontal ledge surface; applying suitable adhesive and finishingthe wall with ceramic tiles, stone or marble, the finish materialmeeting the horizontal ledge surface; and applying silicone or othersuitable sealing material at the joint between tile and ledge surface.According to known methods of installation, when the backer board orother subwall material overlaps the flange, it is usually recommendedthat the backer board not be allowed to touch the ledge in order toprevent trapped water on the ledge from wicking up into the subwall. Inan embodiment of the present invention it is recommended thatinstallation of the shower receptor comprises the steps of leaving a¼-inch gap between the bottom edge of the subwall and the horizontalsurface of the ledge of the shower receptor; and applying a bead ofsilicone sealant or the like in the ¼-inch gap between the subwall andthe horizontal surface of the ledge. This additional sealant step morereliably prevents water from wicking up into the subwall than use of agap only. Maintaining a uniform subwall gap during installation requiresconsiderable skill, while applying sealant is relatively easy even ifthe gap varies in width considerably.

In another embodiment of the present invention it has been found thathaving a flange of height H2+H3 of at least about three inches above theledge area greatly facilitates installation of the subwall materials,leading to improved control of moisture. The increased height overconventional flanges makes it much easier for the installer to lap thesubwall over the flange. Furring strips or other types of shims may beinstalled on the framing stubs to compensate for the thickness of theflange before installing wallboard or mortar systems. When the flangeheight is maintained at least about three inches above the ledge area,furring or shimming is not required for scratch coat and mortar bedsubwalls, thus reducing installation time and cost. This benefit isrealized as long as the membrane, which is installed under the mortarbed, overlaps the flange at least about one inch, while leaving at leastabout one inch gap between the bottom of the membrane and the horizontalledge area. Without the increased flange height above the ledge area,there is not sufficient overlap of the membrane to prevent loss ofoverlap from movement of the membrane during application of the mortarbed, thus requiring furring strips to prevent membrane movement. Withthe higher flange of this invention, there is sufficient overlap of themembrane to accommodate membrane movement during installation withoutneed for furring strips. The higher flange also allows the fasteningscrews to be covered with membrane and subwall materials while easilyretaining a gap between the bottom edge of the subwall and thehorizontal ledge surface.

According to known methods of installation it is known to leave smallgaps or holes in the sealant between the tile or other finish wallmaterial and the shower receptor so that trapped water can escape frombehind the tile. Unfortunately, routine maintenance, often performed byhomeowners or others not skilled in the art, often leads to the holesbeing filled with caulk, leaving no way for the trapped water to escapeinto the receptor. According to an embodiment of the present invention,provision of weep valleys provides a visible reminder to the installerand the maintainer of the shower receptor to leave these areas free ofcaulk. Combining weep valleys with a multi-step ledge area providesparticularly deep valleys that are not only highly visible reminders toinstallers not to caulk, but are also quite difficult to fill withcaulk. Alternately, porous materials, such as grout can be used to fillthe joint between the finish wall and the receptor, while leaving theweep valleys free of all material.

According to another embodiment of this invention, provision of a dual-or tri-step ledge area greatly facilitates installation of both subwalland finish wall materials. The separate steps adapted for the subwalland the finish wall provide guides that guarantee the bottom edge of thesubwall will be elevated above the bottom edge of the finish wall. Thishelps insure that water trapped behind the finish wall will not wick upinto the subwall. When scratch coat and mortar bed construction are usedfor the subwall, the second step provides a convenient float guide formaking a subwall of uniform thickness, while the first step againprovides a guide for the tile or other finish material.

A three-step ledge area provides for ease of use of a single showerreceptor with various types of shower wall construction. A shower wallof backer board and tile may use only the outermost two steps. A showerwall of mortar and lath with tile may use the outer two steps for themortar and lath and the innermost step for the tile. Other multi-steparrangements consistent with the present invention may be envisioned byone skilled in the art.

A test was conducted with an embodiment of the invention similar to FIG.6. Four example shower stalls were constructed using four identical suchshower receptors, glass doors, and various types of wall materials. Theshower receptors were formed using a gel-coat and fiberglass reinforcedresin laminate construction in prototype molds constructed for thepurpose. Each stall had three shower heads directed at the wallsproviding twenty gallons per minute of water flow for eight weeks, fivedays per week. The shower stalls were inspected daily on all fourexterior sides for leaks. After the test period, the stalls werecompletely disassembled to look for evidence of leaks.

The shower stall of Example 1 had cultured marble sheet materials forfinish walls. All joints were sealed with standard silicone caulk, withthe exception of the weep valleys. As one might expect, there was noleakage from the shower because these walls had no grout lines, onlycorner joints, and these wall materials are impervious to water.

The shower stall of Example 2 had a subwall of membrane, lath, andmortar construction, without furring strips, according to theinstallation procedures described above. The finish wall was ceramictile and sanded grout, neither of which was sealed. The ¼-inch gapbetween subwall and ledge was sealed with silicone caulk and the gapbetween tile and ledge was sealed also, but again excluding the weepvalleys. More surprisingly this time, there was again no leakage ofwater out of the shower stall.

The shower stall of Example 3 had a subwall of cementitious backerboard, installed as described above, and a finish wall of ceramic tile.The walls were finished with grout and caulk as in Example 2. Theresults were the same as in Example 2.

The shower stall of Example 4 was constructed with a transparent plasticwindow material as the subwall, in place of the usual backer board. Thenit was finished with tile, grout and caulk as in Example 3. The purposeof the clear backer was to allow observation of the flow of water whichmight leak behind the tile and to confirm visually the excellent resultsof Examples 2 and 3. As explained in the background section, the groutand tile did allow significant amounts of water to leak through andbecome trapped between subwall and finish wall. The water traveledvertically, following the voids created by the use of a v-notched trowelwhen spreading the tile adhesive. The adhesive was purposely appliedwith vertical strokes of the trowel to minimize horizontal flow oftrapped water. When the trapped water reached the bottom of the wall,the silicone caulk stopped the vertical flow, causing it to pool. Whenthe water pooled to a depth of about a half inch, it flowed horizontallyalong the ledge until it reached the weep valleys. Then the waterdrained along the weep valleys back into the shower receptor and downthe drain. No water leaked out of the stall.

The performance of conventional shower receptors in such tests is wellknown by those skilled in the art of installing and replacing showerstalls. If the receptor had been of conventional design in this test,the trapped water would have easily run out of the shower stall over thethreshold. Without weep valleys, or with the inadequate prior artvalleys, the water would have pooled behind the tile much higher than ahalf inch, allowing water to run out over a conventional one-inch flangeas well as over the threshold. Without the threshold disposed higherthan the ledge, the water flowing along the ledge would have noresistance to leaving the receptor. Without the significantly higherflange and the improved overlap of building materials, the pooled waterwould have risen high enough to escape over the flange. Pooled wateralso would have wicked into the subwall and traveled into surroundingporous materials such as studs and drywall.

Thus the present invention provides a shower receptor, including abathtub, with improved control of moisture and trapped water comprisingone or more of the following improvements: the flange is significantlyhigher above the ledge area than prior art receptors; the threshold isdisposed higher than the ledge area where the shower wall materials meetthe receptor; weep valleys are provided in the corners of the ledge areaand where the ledge meets the threshold; the ledge area comprises morethan one step adapted to meet the subwall and finish wall materialswherein the steps are sloped toward the base and each successive stepproceeding inward from the flange toward the base is progressively lowerin elevation; a raised curb is provided along the outer edge of thehorizontal surface of the threshold, the curb adapted to redirect waterthat leaks out of the door enclosure back into the shower receptor; andinstallation instructions for shower receptors with lath and mortarsubwalls include the step of installing the membrane with at least aone-inch overlap of the flange and at least one-inch gap between bottomof membrane and the ledge area of the shower receptor.

Although the present invention has been described in detail for thepurpose of illustration, it is to be understood that such detail issolely for that purpose and that variations can be made therein by oneskilled in the art without departing from the spirit or scope of thepresent invention except as it may be limited by the claims. Theinvention disclosed herein may suitably be practiced in the absence ofany element that is not specifically disclosed herein.

1. A method of constructing a shower stall comprising: (i) placing ashower receptor comprising a ledge and a vertical flange into an alcovewith at least one framed wall; (ii) applying a subwall material to saidwall so that said subwall overlaps said flange; (iii) applying a finishwall material to said wall; (iv) leaving a gap between a bottom edge ofsaid finish wall material and said ledge; and (v) positioning a bottomedge of said subwall material such that the bottom edge of said subwallmaterial is higher than the bottom edge of said finish wall material.(vi) caulking said gap.
 2. The method of claim 1 wherein said gap is atleast about one-quarter inch and said positioning is at least aboutone-quarter inch higher than said bottom edge of said finish wallmaterial.
 3. The method of claim 1 wherein said ledge comprises morethan one step, said bottom edge of said subwall resides within aboutone-quarter inch of one said step and said bottom edge of said finishwall resides within about one-quarter inch of another said step, wherebysaid positioning is facilitated.
 4. The method of claim 1 wherein saidsubwall overlaps said vertical flange at least one inch; and said methodfurther comprises: fastening a membrane to the framing of said framedwall or to a subwall material surface, such that said membrane overlapssaid flange at least one inch, and a gap of at least one inch is leftbetween said membrane and said ledge.
 5. The method of claim 4 whereinsaid vertical flange extends upward at least about three inches abovethe ledge whereby said gap between said membrane and said ledge isfacilitated.
 6. The method of claim 5 wherein the ledge has at least onecorner comprising a valley sloped toward the base; and furthercomprising: leaving each valley substantially free of caulk.
 7. Themethod of claim 6 wherein said ledge comprises more than one stepwhereby said positioning is facilitated.
 8. The method of claim 7further comprising: caulking between said bottom edge of said subwallmaterial and said ledge.
 9. The method of claim 8 wherein said ledgecomprises three or more steps.
 10. A method of constructing a showerstall comprising: (i) placing a one-piece shower receptor in an alcovewith at least one framed wall, said receptor comprising: a base havingsidewalls extending upward from each edge of the base; a thresholdhaving a substantially horizontal surface extending outward from the topedge of at least one of the sidewalls; a ledge having a substantiallyhorizontal surface extending outward from the top edges of the remainingsidewalls; and a vertical flange extending upward from the outer edge ofthe ledge; (ii) applying a subwall material to said wall, overlappingthe flange and leaving a first gap of at least about one-half inchbetween a bottom edge of the subwall material and the horizontal ledgesurface; (iii) applying a finish wall material to said wall; (iv)leaving a second gap of about one-quarter inch between a bottom edge ofsaid finish wall material and the horizontal ledge surface; and (v)caulking said second gap.
 11. The method of claim 10 wherein saidhorizontal ledge surface comprises at least one step adapted to matewith said bottom edge of said subwall material.
 12. The method of claim11 wherein said horizontal ledge surface comprises more than one step.13. The method of claim 12 further comprising: caulking said first gap.14. The method of claim 10 wherein the vertical flange extends upward atleast about three inches above an outer edge of the ledge, and furthercomprising: fastening a membrane to the framing of the alcove or to asubwall surface of the alcove, such that the membrane overlaps theflange at least one inch, and a gap of at least one inch is left betweenthe membrane and the horizontal ledge surface;
 15. The method of claim10 wherein the ledge area has corners comprising valleys sloped towardthe base; and further comprising: leaving the valleys substantially freeof caulk.
 16. A method of constructing a shower stall comprising: (i)placing a shower receptor into an alcove with at least one framed wall,the shower receptor comprising: a base having sidewalls extending upwardfrom each edge of the base; a threshold having a horizontal surfaceextending outward from the top edge of at least one of the sidewalls;and a ledge extending outward from the top edges of the remainingsidewalls, with a vertical flange extending upward from the outer edgeof the ledge, the flange extending higher than the threshold; whereinthe ledge comprises more than one step, a first step disposed closest tothe flange and highest in elevation with respect to the base, and eachsubsequent step lower in elevation and closer to the base; (ii) applyinga subwall material to said wall so that said subwall overlaps saidflange; (iii) leaving a first gap between a bottom edge of the subwallmaterial a step; (iv) applying a finish wall material to said wall; (v)leaving a second gap between a bottom edge of said finish wall materialand a subsequent step; and (vi) caulking said second gap.
 17. The methodof claim 16 further comprising: caulking said first gap.
 18. The methodof claim 16 wherein the vertical flange extends upward at least aboutthree inches above an outer edge of the ledge; said subwall overlapssaid flange at least about one inch; and further comprising: (i)fastening a membrane to the framing of the alcove, so that the membraneoverlaps the flange at least about one inch, and (ii) leaving a gap ofat least about one inch between the membrane and the outer edge of theledge;
 19. The method of claim 16 wherein the ledge has one or morecorners comprising a valley sloped toward the base; and furthercomprising: leaving each said valley substantially free of caulk. 20.The method of claim 19 wherein the ledge comprises three steps.
 21. Themethod of claim 16 wherein the dimensions of the sidewall, base,threshold and ledge of the shower receptor are adapted for use as abathtub.